Agricultural baler with a clamping device for a drawbar drive

Description

[0001] The present application relates to an agricultural baler with at least one traction drive for driving working units of the agricultural baler according to the preamble of independent claim 1, and to a combination of an agricultural machine, in particular a tractor, and such an agricultural baler towed by it according to the preamble of independent claim 13.

[0002] Agricultural balers use traction drives to power the individual working units and functional assemblies. These drives can be either belt or chain drives and must ensure a power transmission appropriate to the machine's output. To guarantee this continuous operation, even under difficult harvesting conditions, the traction drive must be kept under sufficient tension. This is achieved by a tensioning device integrated into the traction drive. During operation of the baler, the traction drive experiences gradual elongation, which is permissible to a certain extent but results in a corresponding change, and in particular a decrease, in the tension of the traction drive.In order to maintain the tension of the traction element necessary for the transmission of driving force, it is therefore necessary to adjust the tension force applied by the tensioning device accordingly during the operation of the agricultural baler.

[0003] From EP 0 126 808 B1, for example, a spring-loaded tensioning device for a V-belt drive is known in this context, in which a compression spring with a pre-tensioning device transmits the tensioning force via a drawbar to a pivotable double lever. A V-belt tensioning roller is mounted at the other end of the double lever, which acts on the V-belt to be tensioned in such a way that the V-belt tension required for the transmission of the drive force is present. The compression spring is arranged on a spring holder between abutments on the drawbar and a fixed bracket connected to the machine frame. The required pre-tension of the compression spring is adjusted by rotating the abutments on the drawbar. Readjusting the tensioning force to be applied during operation of the belt drive is also achieved by rotating the abutments.

[0004] Other tensioning devices for traction drives are generally known from US 5,622,104 A, US 2013 / 298787 A1, US 5,367,865 A and US 4,257,219 A.

[0005] Due to the gradual elongation of the V-belt during operation of the V-belt drive, this type of tensioning device requires the operator to manually readjust the tension applied by the device at regular intervals by rotating the abutments. This process is time-consuming for the operator and requires the application of considerable force to adjust the tension, which is perceived as physically demanding. Furthermore, the use of such a tensioning device is associated with high manufacturing costs, as numerous individual parts are required, the production and assembly of which in turn incurs high manufacturing expenses.

[0006] Based on the prior art described above, the object of the present invention is therefore to provide an agricultural baler with at least one traction drive in which the adjustment of a tensioning force applied to the traction element of the at least one traction drive via a tensioning device is simplified, thus reducing the required time and effort.

[0007] This problem is solved according to the invention by the features of independent claim 1, wherein advantageous further developments of the agricultural baler according to the invention are the subject of the corresponding dependent claims 2 to 12.

[0008] The present invention relates to an agricultural baler with at least one traction drive for powering working units of the agricultural baler. At least one tensioning device is associated with the traction drive, wherein the at least one tensioning device comprises a tensioning element for adjusting a tensioning force exerted on a traction element of the at least one traction drive by means of the tensioning device. The agricultural baler is characterized in that the tensioning element comprises a piston-cylinder unit, wherein a piston of the piston-cylinder unit is connected directly or indirectly, via an additional lever, to a tensioning element of the tensioning device, through which the tensioning force is applied to the traction element of the at least one traction drive, and wherein a lubricant, preferably a grease, can be supplied to the piston-cylinder unit for adjusting the tensioning force exerted on the traction element.

[0009] By lubricating the piston-cylinder unit with lubricant from a lubricant reservoir, the clamping device can apply the clamping force necessary for the proper operation of the traction drive in a particularly straightforward manner. A quantity of lubricant at a specific pressure can be supplied to a cylinder chamber formed by the cylinder's inner wall and the piston's end face. This causes the piston to move within the cylinder in such a way that a clamping force is transmitted to the traction element of the traction drive via the clamping device. This clamping force ensures that the traction element is always sufficiently tensioned, guaranteeing reliable and precise power transmission from the drive's input to its output.

[0010] It is no longer necessary for an operator to laboriously adjust any abutments or nuts manually to set or readjust the clamping force of a clamping device. Furthermore, the use of a clamping element comprising a piston-cylinder unit reduces the effort and costs associated with manufacturing the clamping device and assembling numerous individual components.

[0011] According to the invention, the piston-cylinder unit comprises a lubricant inlet for supplying the lubricant, wherein the lubricant inlet comprises a check valve.

[0012] This ensures that, after the clamping force applied to the traction element by the clamping device has been set, the lubricant does not escape unintentionally from the piston-cylinder unit's cylinder chamber via the lubricant inlet. This would prevent the clamping device from maintaining the set clamping force, resulting in insufficient tension on the traction element of the traction drive. Once the lubricant supply to the piston-cylinder unit is complete, the check valve closes the lubricant inlet valve of the piston-cylinder unit, thus maintaining the set clamping force.

[0013] Preferably, the check valve of the lubricant inlet is designed as a controllable check valve.

[0014] The use of a controllable check valve allows the pressure required to actuate the check valve to be variably adjusted. Furthermore, it is possible to actuate the check valve in the opposite direction to its normal operation, from the closed position to the open position. This allows, for example, the particularly easy removal of lubricant present in the cylinder chamber of the piston-cylinder unit during disassembly or maintenance.

[0015] According to the invention, the agricultural baler comprises a central lubrication system which is fluidly connected to the lubricant inlet of the piston-cylinder unit for supplying the lubricant.

[0016] The fluidic connection between the baler's central lubrication system and the piston-cylinder unit's lubricant inlet allows for automatic adjustment of the clamping force. Once the baler is started, lubricant is continuously pumped at a specific pressure into the piston-cylinder unit's cylinder via the central lubrication system, causing the piston to move within the cylinder. This piston movement also causes the clamping element connected to the piston to move, resulting in the clamping force being transferred to the drive shaft via a contact surface between the clamping element and the drive shaft. The operator is therefore relieved of the need to manually adjust or readjust the clamping force.

[0017] In particular, the central lubrication system comprises at least one lubricant reservoir, one lubricant pump, and one lubricant distribution unit. The lubricant pump is fluidically connected to both the lubricant reservoir and the lubricant distribution unit. The lubricant distribution unit comprises a lubricant inlet, which is fluidically connected to the lubricant pump via a main lubricant line, and at least two lubricant outlets. One of the at least two lubricant outlets is fluidly connected to the lubricant inlet of the piston-cylinder unit via a lubricant distribution line.

[0018] This design makes it particularly easy to connect the central lubrication system already present on the agricultural baler to the clamping device in order to generate the clamping force applied by the clamping device. No complicated and costly modifications to the agricultural baler are necessary. Instead, a lubricant distribution line leading from the lubricant distribution unit of the central lubrication system can be connected to the lubricant inlet of the piston-cylinder unit of the clamping device, thus ensuring that the piston-cylinder unit of the clamping device is supplied with lubricant from a lubricant reservoir of the central lubrication system.

[0019] According to an advantageous embodiment of the invention, the lubricant distribution line connecting the lubricant outlet of the lubricant distribution unit with the lubricant inlet of the piston-cylinder unit comprises a branch line that branches off from the lubricant distribution line, preferably immediately upstream of the lubricant inlet of the piston-cylinder unit. The branch line is fluidically connected to at least one lubrication point on the clamping device, in particular a bearing point of the clamping element and / or at least one bearing point of the additional lever.

[0020] The lubricant already present in the lubricant distribution line, which is supplied to the piston-cylinder unit of the clamping device for adjusting the clamping force of the clamping device, can also be used to lubricate the lubrication points on the clamping device by creating a branch line branching off from this lubricant distribution line.

[0021] Preferably, the branch line includes a check valve or a pressure relief valve.

[0022] Once the necessary clamping force has been generated by supplying lubricant to the cylinder chamber, any excess lubricant, which is continuously delivered from the central lubrication system via the lubricant distribution line, can be used to supply the aforementioned lubrication points. For this purpose, a check valve or pressure relief valve is provided in the branch line, which opens as soon as the required clamping force of the clamping device is reached, meaning that further supply of lubricant to the cylinder chamber of the piston-cylinder unit is no longer necessary.

[0023] In particular, the check valve of the branch line is designed as a controllable check valve or the pressure relief valve of the branch line as an adjustable pressure relief valve.

[0024] The use of a controllable check valve or adjustable pressure relief valve allows the necessary pressure to actuate the check valve or pressure relief valve to be variably adjusted depending on the clamping force to be applied.

[0025] According to an advantageous embodiment of the invention, it is provided that at least one further lubricant outlet of the at least two lubricant outlets of the lubricant distribution unit is fluidically connected to a lubrication point of the agricultural baler by means of a further lubricant distribution line.

[0026] The central lubrication system can therefore continue to be used, as usual, to supply lubrication points on the agricultural baler. In this context, it is possible that one or more of the additional lubricant distribution lines leading from the lubricant distribution unit are fluidically connected to another lubricant distribution unit, with further lubricant distribution lines leading from this second unit to various lubrication points on the agricultural baler.

[0027] According to an advantageous embodiment of the invention, the lubricant inlet of the piston-cylinder unit is designed as a grease nipple for supplying the lubricant, wherein the lubricant can be supplied to the piston-cylinder unit via the grease nipple by means of a grease gun.

[0028] If an agricultural baler does not have a central lubrication system, the clamping force can still be adjusted by supplying lubricant to the cylinder chamber of the piston-cylinder unit. An operator of the agricultural baler can use a grease gun, attached to the grease nipple of the piston-cylinder unit, to direct the lubricant from the grease gun into the cylinder chamber of the piston-cylinder unit, thus setting the required clamping force applied to the traction element by the clamping device.

[0029] According to an advantageous embodiment of the invention, the piston-cylinder unit comprises a lubricant outlet for removing at least part of the lubricant from the piston-cylinder unit, wherein the lubricant outlet comprises a check valve or a pressure relief valve.

[0030] Once the required clamping force is set via the lubricant supply, excess lubricant can escape from the cylinder chamber. A check valve or pressure relief valve, located in the lubricant outlet of the piston-cylinder unit, allows a pressure level to be defined. Exceeding this pressure level causes lubricant to exit the piston-cylinder unit, signaling to the operator that the required clamping force has been set.

[0031] Although this design of the piston-cylinder unit is primarily advantageous when using a grease gun to supply lubricant to the piston-cylinder unit, it is equally conceivable that such a lubricant outlet valve could be used when the piston-cylinder unit is supplied with lubricant via a central lubrication system of the agricultural baler.

[0032] Preferably, the check valve of the lubricant outlet is designed as a controllable check valve or the pressure relief valve of the lubricant outlet is designed as an adjustable pressure relief valve.

[0033] Here too, the use of a controllable check valve or adjustable pressure relief valve allows the necessary pressure for actuating the check valve or pressure relief valve to be variably adjusted depending on the clamping force to be applied.

[0034] In particular, the lubricant outlet of the piston-cylinder unit is fluidically connected to at least one lubrication point on the clamping device, especially a bearing point of the clamping device and / or at least one bearing point of the additional lever.

[0035] If the excess lubricant exiting the lubricant outlet valve of the piston-cylinder unit is not to be wasted, it can advantageously be used to lubricate at least one lubrication point of the clamping device via a flow-technical connection between the lubricant outlet of the piston-cylinder unit and at least one lubrication point.

[0036] According to an advantageous embodiment of the invention, the agricultural baler comprises a control device which is configured to selectively control the valve in the lubricant inlet of the piston-cylinder unit, the valve in the lubricant outlet of the piston-cylinder unit, the valve in the branch line branching off from the lubricant distribution line and / or the lubricant reservoir, the lubricant pump and / or the lubricant distribution unit of the central lubrication system according to a predeterminable or predetermined setting.

[0037] The use of a control unit configured to selectively actuate any existing valves according to a predefined or predetermined setting is advantageous in that it allows for highly precise adjustment of the clamping force of the clamping device while simultaneously ensuring an extremely reliable lubrication supply to the clamping device and / or the agricultural baler. The settings used by the control unit to actuate the valves and / or components of the central lubrication system can either be predefined by an operator or stored in a memory unit connected to the control unit, which the control unit can then access automatically.

[0038] According to an advantageous embodiment of the invention, the tensioning element comprises a tension spring which is arranged between a cylinder and the piston of the piston-cylinder unit.

[0039] The use of an additional tension spring as part of the tensioning element ensures that any losses of tension force in the traction element due to elongation effects during the service life of the traction element drive or during the operation of the agricultural baler are transmitted back to the tensioning device, which signals or triggers an adjustment of the tension force by supplying lubricant to the piston-cylinder unit.

[0040] According to an advantageous further development of the invention, the agricultural baler comprises a plurality of traction drives, each with at least one tensioning device.

[0041] According to an advantageous embodiment of the invention, the at least one traction drive is a belt drive and the tensioning device is a belt tensioning roller.

[0042] According to an advantageous embodiment of the invention, the at least one traction drive is a chain drive and the tensioning device is a chain tensioning wheel.

[0043] Depending on the design of the agricultural baler, the necessary traction drives can be installed to transmit the power required to operate the corresponding working unit or functional unit of the baler. In this context, it is conceivable that all traction drives of the agricultural baler could be belt drives or chain drives. However, it is equally possible that some of the traction drives of the agricultural baler are belt drives and others are chain drives.

[0044] The problem according to the invention is further solved by a combination of an agricultural working machine, in particular a tractor, and an agricultural baler towed by it according to independent claim 13.

[0045] The present invention is described in more detail below with reference to the embodiments illustrated in the figures.

[0046] They show: FIG. 1 a schematic and exemplary representation of a combination according to the invention consisting of an agricultural machine designed as a tractor and an agricultural baler pulled by it; FIG. 2 a schematic and exemplary representation of the agricultural baler according to the invention without chassis and bodywork; FIG. 3 a schematic and exemplary representation of a clamping device according to the invention; FIG. 4 a schematic and exemplary circuit diagram for supplying lubricant to a piston-cylinder unit of the clamping device according to the invention by means of a central lubrication system of the agricultural baler according to the invention; and FIG. 5 a schematic and exemplary circuit diagram for supplying lubricant to the piston-cylinder unit of the clamping device according to the invention by means of a grease gun.

[0047] FIG. 1Figure 1 shows a schematic and exemplary representation of a combination according to the invention consisting of an agricultural machine 1 and an agricultural baler 2 towed by it. The agricultural machine 1 is shown in the figure below. FIG. 1 The depicted representation is designed as a tractor; however, other agricultural machinery 1 designed to pull or tow an agricultural baler 2 are equally conceivable within the scope of the present invention. The agricultural baler 2 is shown in the FIG. 1The illustrated representation depicts a round baler. The round baler has a baler housing consisting of a stationary housing part 3 and a discharge flap 4 pivotally mounted on the stationary housing part 3. The discharge flap 4 is pivotally mounted on the stationary housing part 3 of the baler housing in such a way that it can be moved between a closed and an open position. The baler housing, in particular the stationary housing part 3, is generally arranged on and connected to a chassis 5, via which the round baler is in turn coupled to the agricultural machine 1.

[0048] The press housing, in particular the two housing parts 3 and 4, defines a press chamber 6 into which the harvested crop is conveyed by means 7 for receiving and conveying. These means 7 comprise at least a pick-up, a cutting rotor, and a raker. A detailed description of these means 7 is omitted here, as they are well known.

[0049] Both the stationary housing part 3 and the discharge flap 4 have a plurality of press rollers 8, which are spaced apart from one another and distributed on both housing parts 3, 4, and arranged circumferentially to delimit the press chamber 6. Each of the press rollers 8 is driven, thereby forming or pressing the crop material conveyed into the press chamber 6 into a round bale. The round baler also has a device – not shown in the FIGS. – for wrapping the round bales pressed in the press chamber 6 with a covering, which can be made of film, net, or the like.

[0050] Although the agricultural baler 2 shown in the FIGs. is designed as a round baler with press rollers 8, the invention is equally transferable to round balers with a variable press chamber and square balers.

[0051] According to the invention, the agricultural baler 2 comprises at least one traction drive 9 for driving working units of the agricultural baler 2. For the purposes of this invention, working units of the agricultural baler 2 are defined as all driven functional units of the agricultural baler 2, such as press rollers 8, means 7 for receiving and conveying crop material, a wrapping device, a discharge flap 4, or the like.

[0052] The in FIGS. 2 The illustration schematically and exemplarily shows such an agricultural baler 2 according to the invention with at least one traction drive 9 for driving working units of the agricultural baler 2. In the FIGS. 2The illustration shows not just one such traction drive 9, but rather a multitude of such traction drives 9, each driving one or more working units of the agricultural baler 2. A traction drive 9 can optionally be designed as a belt drive or as a chain drive. With a multitude of traction drives 9, it is possible that some of the traction drives 9 are designed as belt drives and others as chain drives. It is also possible that all traction drives 9 are designed as belt drives or all traction drives 9 are designed as chain drives. Each traction drive 9 comprises at least one drive wheel to supply motive power to the traction drive 9 and at least one driven wheel to transmit the motive power to a working unit.The drive wheel of a traction drive 9 can interact with a driven wheel of another traction drive 9.

[0053] Each of these traction drives 9 is associated with at least one clamping device 10, which is arranged or attached to the agricultural baler 2, in particular to a supporting frame structure of the agricultural baler 2, for example, a supporting frame structure of the stationary housing part 3 and / or the discharge flap 4. By means of the clamping device 10, a traction element 11 of the traction drive 9 is subjected to a clamping force, so that the required drive force is transmitted from the traction drive 9 to the working units of the agricultural baler 2 to be driven. In order to make the clamping force applied by the clamping device 10 to the traction element 11 adjustable, the clamping device 10 comprises a clamping member 12, the inventive design and function of which are described below with reference to the Figures 3 to 5 will be explained in detail.

[0054] Essential for the clamping device 10 according to the invention, which is shown schematically and by way of example in FIG. 3 What is shown in detail is that the tensioning element 12 comprises a piston-cylinder unit 13 to which a lubricant can be supplied to adjust a tensioning force exerted on the traction element 11 of the traction element drive 9.

[0055] The piston-cylinder unit 13 comprises a cylinder 14 and a piston 15 movably arranged within the cylinder 14. The piston 15 is connected directly or indirectly, via an additional lever 16, preferably a lever 16 comprising two lever arms 17, 18, to a clamping element 19 of the clamping device 10, through which the clamping force is applied to the traction element 11 of the traction drive 9. The clamping device 10 can be arranged or attached to the agricultural baler 2 via the cylinder 14. The piston 15 comprises a piston head 20 and a piston rod 21 adjoining the piston head 20. Depending on the configuration of the traction drive 9, either as a belt drive or as a chain drive, the clamping element 19 is designed accordingly as a belt tensioning wheel or as a chain tensioning wheel. As already indicated, the clamping force is applied by means of the clamping element 19.the adjustment of the same such that a lubricant is supplied to the piston-cylinder unit 13. The lubricant, which can also be used for lubricating lubrication points of the agricultural baler 2, is preferably a grease.

[0056] In order to supply the piston-cylinder unit 13 with lubricant for adjusting the clamping force exerted on the traction element 11 of the traction element drive 9 by means of the clamping device 10, the piston-cylinder unit 13 includes a lubricant inlet 22, which is formed on the cylinder 14 of the piston-cylinder unit 13. The lubricant inlet 22 includes a check valve 23, which is located in the FIGS. 4 and 5The arrangement is such that the lubricant can flow into the cylinder 14 and into a cylinder chamber 24, which is formed by an inner wall of the cylinder 14 and an end face of the piston 15, while preventing the lubricant from flowing out of the cylinder chamber 24. According to one embodiment, the check valve 23 in the lubricant inlet 22 can be controllable, so that the opening pressure for the check valve 23 can be flexibly adjusted.

[0057] The piston-cylinder unit 13 can further comprise a lubricant outlet 25, which is also formed on the cylinder 14 of the piston-cylinder unit 13. The lubricant outlet 25 optionally includes a check valve 26 or a pressure relief valve 26, which is located in FIG. 5As shown, a portion of the lubricant supplied to the cylinder 14 for adjusting the clamping force can flow out of the cylinder chamber 24 when a predeterminable or predetermined pressure value is exceeded. According to one embodiment, the check valve 26 or the pressure relief valve 26 in the lubricant outlet 25 can be controllable or adjustable, so that an opening pressure for the check valve 26 or pressure relief valve 26 can be flexibly adjusted. The lubricant outlet 25 can also be closed with a closure (not shown in the figures).

[0058] The clamping element 12 of the clamping device 10 can further comprise a clamping spring 27, which is arranged between the cylinder 14 and the piston 15 of the piston-cylinder unit 13. The clamping spring 27 is preferably arranged such that one end is supported against a part of the cylinder 14 and the other end is connected to the piston 15. By supplying lubricant to the piston-cylinder unit 13, and thus causing the piston 15 to move within the cylinder 14, the clamping spring 27 is pre-tensioned, the clamping force being applied to the traction element 11 of the traction drive 9 via the direct or indirect coupling of the piston 15 to the clamping element 19.

[0059] The supply of lubricant to the piston-cylinder unit 13 for adjusting the clamping force exerted on the tension member 11 can be accomplished in various ways. According to one embodiment, which is described in FIG. 4As shown in the figure, the agricultural baler 2 includes a so-called central lubrication system 28, which primarily serves to supply lubricant, in particular grease, to the lubrication points of the agricultural baler 2. This central lubrication system 28 also serves to supply the piston-cylinder unit 13 with lubricant for adjusting the clamping force exerted on the traction element 11. For this purpose, the central lubrication system 28 is fluidically connected to the lubricant inlet 22 of the piston-cylinder unit 13 for the supply of the lubricant.

[0060] The central lubrication system 28 comprises at least one lubricant reservoir 29, a lubricant pump 30, and a lubricant distribution unit 31. The lubricant pump 30 is fluidically connected to both the lubricant reservoir 29 and the lubricant distribution unit 31 and pumps the lubricant, in particular the grease, from the lubricant reservoir 29 to the lubricant distribution unit 31. For this purpose, the lubricant distribution unit 31 includes a lubricant inlet 32, which is fluidly connected to the lubricant pump 30 by means of a lubricant main line 33. The lubricant distribution unit 31 further comprises at least two lubricant outlets 34a-34n. One lubricant outlet 34a of the at least two lubricant outlets 34a-n is fluidly connected to the lubricant inlet 22 of the piston-cylinder unit 13 via a lubricant distribution line 35a.At least one of the at least two lubricant outlets 34a-n of the lubricant distribution unit 31 is fluidically connected to a lubrication point of the agricultural baler 2 by means of a further lubricant distribution line 35b. The lubricant distribution unit 31 can comprise not only one further lubricant outlet 34b, but rather a plurality of further lubricant outlets 34b-n, each of which is fluidly connected to a corresponding lubrication point of the agricultural baler 2 by a further lubricant distribution line 35b-n. The further lubricant distribution lines 35b-n can also be fluidly connected to further lubricant distribution units (not shown in the figures), from which a plurality of lubricant distribution lines then branch off, leading to lubrication points of the agricultural baler 2.

[0061] The central lubrication system 28, used for lubricating the lubrication points of the agricultural baler 2, can therefore also be used to adjust the clamping force of the clamping device 10. For this purpose, the lubricant, in particular the grease, is supplied to the piston-cylinder unit 13 via the central lubrication system 28 at a pressure sufficient to apply the desired or necessary clamping force to the traction element 11 of the traction drive 9. Thus, an operator does not need to adjust the clamping device 10 manually. Instead, the clamping force of the clamping device 10 is adjusted automatically as soon as the agricultural baler 2 is put into operation.

[0062] According to an advantageous further development of this embodiment, the lubricant distribution line 35a, which connects the lubricant outlet 34a of the lubricant distribution unit 31 with the lubricant inlet 22 of the piston-cylinder unit 13, may comprise a branch line 36 that branches off from the lubricant distribution line 35a, preferably immediately upstream of the lubricant inlet 22 of the piston-cylinder unit 13. The branch line 36 is fluidically connected to at least one lubrication point on the clamping device. Preferably, the branch line 36 is fluidically connected to a bearing point 37 of the clamping device 19 and / or at least one bearing point 38 of the additional lever 16, if one is used. Furthermore, the branch line 36 preferably comprises a check valve 39 or a pressure relief valve 39. This check valve 39 or pressure relief valve 39 may also preferably be controllable.It should be an adjustable valve.

[0063] If the pressure in the lubricant distribution line 35a exceeds the pressure required to apply the clamping force, the check valve 39 or the pressure relief valve 39 opens, allowing the lubrication points of the clamping device 10 to be supplied with lubricant, in particular grease, via the branch line 36. In this configuration, the lubricant outlet 25 is preferably closed with the valve, so that no lubricant can escape from the cylinder chamber 24 of the piston-cylinder unit 13 through this outlet, but only flows via the branch line 36 to the lubrication points of the clamping device 10.Alternatively, the pressure set for opening the check valve 26 or the pressure relief valve 26 can be selected to be higher than the pressure required to open the check valve 39 or pressure relief valve 39, so that when the necessary pressure for setting the clamping force is reached, the lubricant is always supplied to the lubrication points of the clamping device 10 via the branch line 36.

[0064] According to another embodiment, which in FIG. 5As shown, the lubricant inlet 22 of the piston-cylinder unit 13 is designed as a grease nipple for supplying the lubricant, in particular grease. Unlike the embodiment described above, the lubricant, in particular the grease, is therefore not supplied to the piston-cylinder unit 13 via a central lubrication system 28, but rather introduced into the cylinder chamber 24 of the piston-cylinder unit 13 via a grease gun 40 attached to the grease nipple, whereby the clamping device 10 applies the clamping force to the traction element 11 of the traction element drive 9.

[0065] In such a design, the lubricant outlet 25 of the piston-cylinder unit 13 is preferably not closed with a valve, so that when the necessary pressure for adjusting the clamping force is reached, excess lubricant can escape via the lubricant outlet 25 of the piston-cylinder unit 13, which is equipped with the check valve 26 or pressure relief valve 26. Optionally, the lubricant outlet 25 can be fluidically connected to at least one lubrication point on the clamping device 10, in particular the bearing point of the clamping element 19 and / or at least one bearing point of the additional lever 16, so that the excess lubricant can be used to lubricate these points.

[0066] It is still possible to use the method described above and in FIG. 4In the illustrated embodiment with a central lubrication system 28, an optional manual supply via a grease gun can also be implemented. For this purpose, an additional inlet (not shown in the FIGS.) or an additional branch line (not shown in the FIGS.), preferably with a check valve or pressure relief valve, can be provided on the lubricant distribution line 35a, to which the grease gun can be connected in order to supply lubricant to the cylinder chamber 24 for adjusting the clamping force.

[0067] The agricultural baler 2 preferably further comprises a control device (not shown in the figures). This device is configured to selectively control either the valve 23 in the lubricant inlet 22 of the piston-cylinder unit 13, the valve 26 in the lubricant outlet 25 of the piston-cylinder unit 13, the valve 39 in the branch line 36 branching off from the lubricant distribution line 35a, and / or the lubricant reservoir 29, the lubricant pump 30, and / or the lubricant distribution unit 31 of the central lubrication system 28 according to a predeterminable or predetermined setting. The setting can be provided via a control unit on the agricultural baler 2 or on the agricultural machine 1 that pulls or tows the agricultural baler 2 (shown in the figures).The operating device (not shown) connected to the control unit for data transmission is set by the operator and / or stored in a storage unit connected to the control unit for data transmission. Unless the valves 23, 26, 39 are designed as adjustable or controllable valves, they are nevertheless preset before commissioning the agricultural baler 2 such that the necessary clamping force can be adjusted via a supply of lubricant, in particular grease, according to the embodiments described above. Reference symbol list

[0068] 1 agricultural machinery 26 Check valve / pressure relief valve 2 agricultural baler 27 Tension spring 3 fixed housing part 28 central lubrication system 4 Ejection flap 29 Lubricant reservoir 5 chassis 30 Lubricating pump 6 Press chamber 31 Lubricant distribution unit 7 Means for picking up and conveying harvested crops 32 Lubricant inlet 8 Press roller 33 Main lubricant line 9 Traction drive 34a-n Lubricant outlet 10 Clamping device 35a-n Lubricant distribution line 11 Traction 36 Branch Management 12 Tensioning member 37 bearing point 13 Piston-cylinder unit 38 bearing point 14 cylinder 39 Check valve / pressure relief valve 15 Pistons 40 Grease press 16 lever 17 Lever arm 18 Lever arm 19 Clamping device 20 Piston head 21 piston rod 22 Lubricant inlet 23 Check valve / pressure relief valve 24 Cylinder space 25 Lubricant outlet

Claims

1. Agricultural baler (2) having at least one traction mechanism drive (9) for driving working units of the agricultural baler (2), wherein at least one tensioning device (10) is assigned to the traction mechanism drive (9), wherein the at least one tensioning device (10) comprises a tensioning member (12) for adjusting a tensioning force exerted by means of the tensioning device (10) on a traction mechanism (11) of the at least one traction mechanism drive (9), wherein the tensioning member (12) comprises a piston-cylinder unit (13), wherein a piston (15) of the piston-cylinder unit (13) is connected directly or indirectly via an additional lever (16) to a tensioning means (19) of the tensioning device (10), via which tensioning means the tensioning force is applied to the traction mechanism (11) of the at least one traction mechanism drive (9), wherein a lubricant, preferably a lubricating grease, can be supplied to the piston-cylinder unit (13) for adjusting the tensioning force exerted on the traction mechanism (11), wherein the piston-cylinder unit (13) comprises a lubricant inlet (22) for supplying the lubricant, wherein the lubricant inlet (22) comprises a, preferably controllable, non-return valve (23), characterized in that the agricultural baler (2) comprises a central lubrication system (28) which is fluidically connected to the lubricant inlet (22) of the piston-cylinder unit (13) for supplying the lubricant.

2. Agricultural baler (2) according to Claim 1, characterized in that the central lubrication system (28) comprises at least one lubricant container (29), a lubricant pump (30) and a lubricant distributor unit (31), wherein the lubricant pump (30) is fluidically connected both to the lubricant container (29) and to the lubricant distributor unit (31), wherein the lubricant distributor unit (31) has a lubricant inlet (32), which is fluidically connected to the lubricant pump (30) by means of a lubricant main line (33), and at least two lubricant outlets (34a-n), wherein one lubricant outlet (34a) of the at least two lubricant outlets (34a-n) is fluidically connected to the lubricant inlet (22) of the piston-cylinder unit (13) via a lubricant distribution line (35a).

3. Agricultural baler (2) according to Claim 2, characterized in that the lubricant distribution line (35a) connecting the lubricant outlet (34a) of the lubricant distributor unit (31) to the lubricant inlet (22) of the piston-cylinder unit (13) comprises a branch line (36) which branches off from the lubricant distribution line (35a), preferably directly, upstream of the lubricant inlet (22) of the piston-cylinder unit (13), wherein the branch line (36) is fluidically connected to at least one lubrication point on the tensioning device (10), in particular a bearing point (37) of the tensioning means (19) and / or to at least one bearing point (38) of the additional lever (16), wherein, preferably, the branch line (36) comprises an, in particular controllable, non-return valve (39) or an, in particular adjustable, pressure limiting valve (39).

4. Agricultural baler (2) according to either of Claims 2 and 3, characterized in that at least one further lubricant outlet (34b-n) of the at least two lubricant outlets (34a-n) of the lubricant distributor unit (31) is fluidically connected to a lubrication point of the agricultural baler (2) by means of a further lubricant distribution line (35b-n).

5. Agricultural baler (2) according to one of Claims 1 to 4, characterized in that the lubricant inlet (22) of the piston-cylinder unit (13) for supplying the lubricant is designed as a lubricating nipple, wherein the lubricant can be supplied to the piston-cylinder unit (13) via the lubricating nipple by means of a grease gun (40) .

6. Agricultural baler (2) according to one of Claims 1 to 5, characterized in that the piston-cylinder unit (13) comprises a lubricant outlet (25) for discharging at least some of the lubricant from the piston-cylinder unit (13), wherein the lubricant outlet (25) comprises a, preferably controllable, non-return valve (26) or a, preferably adjustable, pressure-limiting valve (26).

7. Agricultural baler (2) according to Claim 6, characterized in that the lubricant outlet (25) of the piston-cylinder unit (13) is fluidically connected to at least one lubrication point on the tensioning device (10), in particular to a bearing point (37) of the tensioning means (19) and / or to at least one bearing point (38) of the additional lever (16).

8. Agricultural baler (2) according to one of Claims 1 to 7, characterized in that the agricultural baler (2) comprises a control device which is configured to selectively actuate the valve (23) in the lubricant inlet (22) of the piston-cylinder unit (13), the valve (26) in the lubricant outlet (25) of the piston-cylinder unit (13), the valve (39) in the branch line (36) branching off from the lubricant distribution line (35a), and / or the lubricant container (29), the lubricant pump (30) and / or the lubricant distributor unit (31) of the central lubrication system (28) in accordance with a predefinable or predefined stipulation.

9. Agricultural baler (2) according to one of Claims 1 to 8, characterized in that the tensioning member (12) comprises a tensioning spring (27) which is arranged between a cylinder (14) and the piston (15) of the piston-cylinder unit (13).

10. Agricultural baler (2) according to one of Claims 1 to 9, characterized in that the agricultural baler (2) comprises a multiplicity of traction mechanism drives (9) each having at least one tensioning device (10).

11. Agricultural baler (2) according to one of Claims 1 to 10, characterized in that the at least one traction mechanism drive (9) is a belt drive and the tensioning means (19) of the tensioning device (10) is a belt tensioning pulley.

12. Agricultural baler (2) according to one of Claims 1 to 11, characterized in that the at least one traction mechanism drive (9) is a chain drive and the tensioning means (19) of the tensioning device (10) is a chain tensioning sprocket.

13. Combination of an agricultural working machine (1), in particular a tractor, and an agricultural baler (2) pulled by the latter, characterized in that the agricultural baler (2) is designed according to one of Claims 1 to 12.